Influence of alamethicin on the passive water permeability of model lipid membranes and on the morphology of giant lipid vesicles

The water permeability of the membrane of a lipid vesicle in the presence of the natural peptide alamethicin was studied at various constant hydrostatic pressure differences between the inside and outside of the vesicle. Each pressure difference was created by sucking a vesicle into a micropipette at a given sucking pressure. It was determined that the presence of a 7 μM total alamethicin concentration in the experimental cell increased the membrane permeability towards water by about 15 times. A new experimental technique for the investigation of the morphological behavior of giant vesicles was developed. It was used for the study of the influence of alamethicin on the morphology of giant SOPC vesicles. Strong and reversible changes from a quasi-sphere to a discocyte were observed at 7 μM alamethicin concentration in the aqueous phase.[PUBLICATION ABSTRACT]